[css-sizing] Whoops, finish deleting the stretch-fit extrinsic sizing section.

Author: tabatkins

css-sizing-3/Overview.bs

@@ -476,13 +476,6 @@ Extrinsic Size Determination</h2>
 		<dfn export>Extrinsic sizing</dfn> determines sizes based on the context of an element,
 		without regard for its contents.
 
-<h3 id="stretch-fit-sizing">
-Stretch-fit Sizing</h3>
-
-	The inner <a>stretch-fit inline size</a> of a box is&hellip;
-
-
-
 
 <h3 id="percentage-sizing">
 	Percentage Sizing</h3>